Recycling of fiber-faced floor coverings or carpets by mechanical shredding is commonly known in the art. Shredding separates most of the entrapped dirt and powderized binders or fillers. In many instances, the shredded carpet is converted into congealed granules or small solid pieces, which may be mixed with additional binders or compacted to form sheets, usually reinforced with glass scrims, to serve as stabilizing backings for tufted carpet tiling. Other uses of granulated recycled carpet materials include various molded plastic structures used in construction, furniture, or packaging.
Higher end uses of conventional recycled carpeting include cushioning structures. Such cushioning structures can be produced from carpet fibers that are pneumatically or centrifugally separated from trapped dirt or powderized binders. The separated fibers are used to prepare a non-woven web through various conventional textile web-forming methods including garnetting, air-laying, and cross-lapping. Web-forming is followed by dimensional stabilization methods including stitchbonding and needlepunching. Needlepunching is a preferred method, because it provides the benefit of orienting a portion of the fibers in the normal direction, thereby improving cushion or compressive resilience. Frequently, binders are added to the textile sheet. The binders are selected so they soften, melt or set at temperatures lower than the melting temperatures of the fibers. Typically, the recycled fibers include polyolefins which start to soften around 125° C. Most commonly, the conventional webs reclaimed from recycled carpets do not have the facial integrity or durability to serve as directly exposed floor covering, and can only serve as carpet underlays under tufted or woven carpeting.
Commonly owned, co-pending U.S. patent application Ser. Nos. 10/307,186, 10/611,470 and 10/611,769 and commonly owned U.S. Pat. Nos. 6,936,327 and 7,255,761 disclose floor coverings wherein cushion is provided by the backings, which may include recycled carpeting. These backings are covered with fibrous face layers attached to the backing with a layer of adhesive therebetween. The face layers present the face of the carpet and are embossable to create a three dimensional configuration that provides stability to the floor coverings and minimizes planar expansion and contraction with temperature and humidity variations, thereby preventing warping, bulging or seam-separation on the floor.
The relative ease with which a face layer stabilizes fibrous backings of this type, which may have variable structural integrity, raises the possibility that such backings could also be formed from carpeting directly after shredding, without the use of textile processing or needlepunching, and without excluding short broken fibers or thermoplastic adhesive granules which tend to fall out during conventional carding, garneting, and needlepunching processes. It is also noted by the Inventor that most of the structures disclosed in the above commonly owned applications and patents, and a large percentage of commercial carpeting, contain polyolefins or other low-melt thermoplastic components, which soften and become tacky and bondable with heat and pressure at temperatures above 125° C. Such temperatures are well below the melting/softening temperature of the rest of the components. For instance, polyester or nylon soften and melt around 250° C., and natural fibers or aramids stay intact at temperatures well above 250° C. The percentage of polyolefins or other low-melt components in most commercial carpeting varies between 20% and 65%, raising the possibility that the entire dispersed mass can be thermally consolidated using appropriate temperatures, pressures and exposure times to produce backings for structures disclosed in the above commonly owned patent applications and patents. Alternatively, the dispersed mass can be compression molded to produce durable cushioning sheeting for end uses such as carpet underlays, shock absorbing pads, automotive floor or tank coverings, and the like.